title: Delayed formation of splenic pseudoaneurysm following nonoperative management in blunt splenic injury: multi-institutional study in Osaka, Japan.
abstract: BACKGROUND
  Delayed rupture is well-known as a severe complication after splenic injury treated with nonoperative management (NOM). The incidence and timing of splenic pseudoaneurysm (SPA) formation, which is a cause of delayed rupture following splenic injury, have not been thoroughly investigated, and the timing of follow-up computed tomography (CT) is controversial. The objective of this study was to clarify the incidence and timing of both the delayed formation and spontaneous resolution of SPA following splenic injuries treated with NOM in several trauma centers in Japan.
  
  
  METHODS
  This was a retrospective review of all patients with documented blunt splenic injury who were treated with NOM from 2003 through 2010 in five trauma and critical care centers.
  
  
  RESULTS
  The present study consisted of 104 patients, including 16 patients (15.4%) with delayed formation of SPA (7 patients with Grade II and 9 with Grade III) during their clinical course. SPA was diagnosed with enhanced CT at a mean (SD) of 4.6 (2.1) hospital days (range, 1-8 days) after admission. Delayed formation of SPA was found in 30.4% of Grade II injuries and in 18.4% of Grade III injuries. Eight patients with delayed formation of SPA were observed without transcatheter arterial embolization during their entire stay. These SPAs were spontaneously occluded on follow-up enhanced CT or angiography. Spontaneous occlusion of SPA was confirmed at 5.2 (2.6) hospital days (range, 2-10 days) after diagnosis of delayed SPA.
  
  
  CONCLUSIONS
  Delayed formation of SPAs was recognized with enhanced helical CT in 15% of all patients during hospital Days 1 to 8. About one half of the SPAs had occluded spontaneously without therapeutic intervention. Our results suggested that follow-up enhanced CT performed approximately 1 week after splenic injury may be useful to detect delayed SPA formation.
  
  
  METHODS
  Epidemiologic study, level III.
authors.affiliation: From the Department of Traumatology and Acute Critical Medicine (T.M., H.O., K.S., Y.K., T.S.), Osaka University Graduate School of Medicine, Osaka, Japan; Emergency and Critical Care Medical Center (T.F.), Osaka Police Hospital, Osaka, Japan; Department of Emergency and Critical Care (Y.N.), Osaka General Medical Center, Osaka, Japan; Senri Critical Care Medical Center (Y.I.), Osaka Saiseikai Senri Hospital, Osaka, Japan; OsakaPrefectural Nakakawachi Medical Center of Acute Medicine (H.H.) Osaka; and Department of Emergency Medicine (O.T.), Unit of Clinical Medicine, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Muroya
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Ogura
authors.forename: Kentaro
authors.initials: K
authors.lastname: Shimizu
authors.forename: Osamu
authors.initials: O
authors.lastname: Tasaki
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Kuwagata
authors.forename: Takashi
authors.initials: T
authors.lastname: Fuse
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Nakamori
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Ito
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hino
authors.forename: Takeshi
authors.initials: T
authors.lastname: Shimazu
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D017541:Aneurysm, False / Q000000981:diagnostic imaging / Q000209:etiology*; D021721:Balloon Occlusion; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D013154:Spleen / Q000293:injuries*; D013157:Splenic Artery / Q000293:injuries*; D013997:Time Factors; D036542:Tomography, Spiral Computed; D014949:Wounds, Nonpenetrating / Q000150:complications / Q000628:therapy*; D055815:Young Adult